Black Medic (Medicago lupulina): Identification & Selective Herbicide Matrix
Quick Agronomic Summary
Fluroxypyr, Triclopyr, or Quinclorac (Drive XLR8) effectively kills Black Medic between 60°F and 85°F.
- Diagnostic Marker 1: Trifoliate leaves where the center leaflet is on a distinctly longer stalk
- Diagnostic Marker 2: Trailing, square stems radiating from a taproot without rooting at nodes
- Diagnostic Marker 3: Small, bright yellow clover-like flower clusters turning into black, coiled seedpods
What herbicide kills Black Medic?
Fluroxypyr, Triclopyr, or Quinclorac (Drive XLR8) effectively kills Black Medic between 60°F and 85°F.
Black medic is an indicator of low-nitrogen, dry, compacted soil. Quinclorac or TZone eliminates the taproot completely.
When to apply herbicide for Black Medic?
Apply in late spring when seedlings are young, or in early fall before seed maturation.
Fertilizing lawns with appropriate nitrogen levels helps turf outcompete this legume.
EPA-Registered Herbicides Labeled for Black Medic
The table below compares all selective herbicides in our database that control Black Medic, including active ingredient groups, application temperature limits (°F), and surfactant requirements.
| Brand Name & EPA Reg. | Active Ingredient & WSSA Group | Temp Window (°F) | Surfactant & Mixing Protocol | Where to Buy |
|---|---|---|---|---|
| Tenacity EPA Reg. 100-1267 |
Mesotrione 40% Group 27 (HPPD Inhibitor) |
55°F – 85°F Rainfast: 6h |
Always apply with Non-Ionic Surfactant (NIS) at 1 tsp (5 mL) per gallon of water for post-emergent applications. Causes temporary white bleaching on susceptible weeds and turf tips. | Check Price at DoMyOwn View on Amazon |
| Drive XLR8 EPA Reg. 7969-272 |
Quinclorac 18.92% Group 4 (Synthetic Auxin / Quinoline Carboxylic Acid) |
60°F – 85°F Rainfast: 1h |
Requires Methylated Seed Oil (MSO) surfactant at 1.5 tbsp (0.75 fl oz) per gallon of water for effective cuticle penetration on multi-tiller crabgrass. | Check Price at DoMyOwn View on Amazon |
| SpeedZone Lawn Weed Killer EPA Reg. 2217-833 |
2,4-D 28.57%, Mecoprop-p 5.88%, Dicamba 1.71%, Carfentrazone-ethyl 0.62% Group 4 + Group 14 (Synthetic Auxins + PPO Inhibitor) |
50°F – 85°F Rainfast: 3h |
Do NOT add surfactant. Adding NIS or MSO increases ester volatility and causes severe contact burn on desirable cool-season turf. | Check Price at DoMyOwn View on Amazon |
| TZone SE EPA Reg. 2217-920 |
Triclopyr 7.72%, 2,4-D 29.36%, Dicamba 2.22%, Sulfentrazone 0.66% Group 4 + Group 14 (Pyridine Auxin + Phenoxy + PPO Inhibitor) |
50°F – 80°F Rainfast: 3h |
Do NOT mix with surfactant when temperatures exceed 75°F. In cool spring or fall conditions (55°F–70°F), 0.5 tsp NIS per gallon improves waxy leaf penetration on Wild Violet. | Check Price at DoMyOwn View on Amazon |
| Celsius WG EPA Reg. 432-1507 |
Thiencarbazone-methyl 8.7%, Iodosulfuron-methyl-sodium 1.9%, Dicamba 57.4% Group 2 + Group 4 (ALS Inhibitors + Benzoic Acid Auxin) |
65°F – 95°F Rainfast: 4h |
Apply with Non-Ionic Surfactant (NIS) at 1 tsp per gallon of water. Specifically engineered not to stunt warm-season turf during summer heat up to 95°F. | Check Price at DoMyOwn View on Amazon |
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Turfgrass Compatibility Matrix for Black Medic Herbicides
Always verify that your chosen herbicide is safe for your specific lawn grass before broadcast spraying:
| Herbicide | KBG | Tall Fescue | Ryegrass | Bermuda | St. Aug | Zoysia | Centipede | Bahia |
|---|---|---|---|---|---|---|---|---|
| Tenacity | SAFE | SAFE | SAFE | AVOID ACTIVELY GROWING | SOD PRODUCTION ONLY | DAMAGE RISK | SAFE | AVOID |
| Drive XLR8 | SAFE | SAFE | SAFE | SAFE | AVOID | SAFE | AVOID | AVOID |
| SpeedZone Lawn Weed Killer | SAFE | SAFE | SAFE | SAFE | AVOID | SAFE | AVOID | SAFE |
| TZone SE | SAFE | SAFE | SAFE | DAMAGE RISK | AVOID | SAFE | AVOID | AVOID |
| Celsius WG | AVOID | AVOID | AVOID | SAFE | SAFE | SAFE | SAFE | AVOID |
How to Distinguish Black Medic from Lookalike Weeds
| Lookalike Species | Key Botanical & Diagnostic Difference |
|---|---|
| White Clover | White clover has white flowers and leaflets radiating equally without an extended center petiole; Black medic has yellow flowers and a stalked middle leaflet. |
| Yellow Woodsorrel | Oxalis has distinctly heart-shaped notched leaflets, while Black Medic leaflets are oval with small toothed tips. |